Muslims members of the British parliament have been sent a series of suspicious packages over the past 24 hours, prompting a response by police.

Officers were called to the parliamentary estate on Monday and again on Tuesday. Two people were hospitalised as a precaution before the items were deemed not to be hazardous.

Parliament has received four such packages over the past 24 hours, police told Business Insider. Three of the MPs in question have said the packages came with aggressive letters attacking their religion.

Mohammad Yasin received a package on Monday, his office confirmed to Business Insider. Rushanara Ali, and Rupa Huq have both tweeted to say they received similar packages. Afzal Khan also received a package but did not open it, his office told BI in a statement.

The packages sent to Yasin, Ali, and Huq contained letters advertising “Punish A Muslim Day,” which listed Islamophobic actions and the number of points given for performing them,The Guardian reported.

The letter was also sent to households nationwide, said Tell MAMA, a charity that investigates anti-Muslim acts in the UK.

“Punish A Muslim Day” letters are being sent to families in East London. The letter details a point system for each action & a reward. For example pulling a Muslim women’s hijab is 25 points, throwing acid is 50 points and burning or bombing a mosque is a whole 1,000 points. pic.twitter.com/6kmCrDrXt0

Labour leader Jeremy Corbyn called the letters “utterly contemptible” called for unity against “vile Islamophobia.”

Huq told the BBC the package sent to her on Monday contained a “low-level noxious substance and an offensive letter.”

Lab MP @RupaHuq tells me a member of staff is being taken to hospital after opening a suspect package -2 MPs from Muslim backgrounds were targeted yesterday and she says police say the package contained a 'low level' noxious substance & an offensive letter pic.twitter.com/6MAd4ha8fm